1. Field of the Invention
The present invention relates to USB connectors conforming to a USB 2.0 specification and a USB 3.0 specification, and more particularly to a USB port, a USB plug and a connection structure thereof.
2. Description of the Related Art
Universal serial bus (USB) is a specification to establish communication between devices and a host controller (e.g. personal computers). USB is intended to replace many varieties of serial and parallel ports. USB can connect computer peripherals such as mice, keyboards, digital cameras, printers, personal media players, flash drives, and external hard drives. For many of those devices, USB has become the standard connection means. USB was designed for personal computers, but it has become commonplace on other devices such as smartphones, personal digital assistants (PDAs) and video game consoles, and as a power cord between a device and an AC adapter plugged into a wall plug for charging.
USB 1.0 released in 1996 and USB 1.1 released in 1998 provide a Low-Speed 1.5 Mbps subchannel for keyboards and mice and a Full-Speed channel at 12 Mbps. Hi-Speed USB 2.0 released in 2001 jumps the top rate to 480 Mbps, while SuperSpeed USB 3.0 released in 2008 provides a huge 10× increase to 4.8 Gbps.
Currently, USB 2.0 is the most common and widely used interface, but USB 3.0 can provide amazing speed. In order to let USB 3.0 become popular, it is important to provide USB connectors which conform to a USB 2.0 specification and a USB 3.0 specification.